When asking, what is the sun made of, you have to start with the fact that the sun holds an incredible 99.86% of our entire solar system’s mass and dominates our cosmic neighborhood completely. Its core reaches temperatures of 15 million degrees Celsius, which powers a nuclear fusion reactor. This massive reactor converts 600 billion kilograms of hydrogen into helium each second.
The sun’s composition tells an interesting story. Hydrogen makes up 74% while helium accounts for 24% of its mass. Heavier elements like oxygen, carbon, neon, and iron form the remaining 2%. Scientists classify it as a G-type main-sequence star with a surface temperature of 5,500 degrees Celsius – perfect conditions that enable life on Earth.
Let’s explore the sun’s complex structure in this piece, from its blazing core to its outer atmosphere. You’ll find how nuclear fusion powers our star and why its corona heats up to 2 million degrees Celsius. Current research continues to reveal fascinating details about our star’s composition through its various layers.
The Sun’s Core: Nuclear Fusion Factory
Image Source: EUROfusion
The solar core acts as an incredible powerhouse that sits at the heart of our star. This dense region stretches from the center to about 0.2 of the solar radius (around 139,000 kilometers). The core powers everything our sun does. The conditions here are so extreme that they challenge our earthly understanding.
Temperature and Pressure Conditions at 15 Million Degrees
The core maintains mind-boggling temperatures of approximately 15 million degrees Celsius (27 million degrees Fahrenheit). These temperatures create an environment where normal chemistry simply can’t exist. Matter exists in its fourth state – plasma – and electrons completely break free from atomic nuclei.
The gravitational pressure at the core reaches approximately 2.477 x 10^11 bar. This creates a density of about 150,000 kg/m³ (150 g/cm³), which means the core is 150 times denser than water. This is a big deal as it means that the core’s density is 8 times greater than gold (19.3 g/cm³) and 13 times more than lead (11.3 g/cm³).
These extreme conditions create the perfect setting for nuclear fusion. The core generates power at a modest rate of about 276.5 watts per cubic meter at its center. The core’s massive volume turns this modest rate into an enormous total energy output.
Hydrogen-to-Helium Conversion Process
Nuclear fusion happens through a process called the proton-proton chain reaction. The extreme heat makes hydrogen nuclei (protons) move at incredible speeds – averaging about 1000 kilometers per second. Protons naturally repel each other because of their positive charge. The core’s intense pressure and temperature let them overcome this barrier and collide.
Protons fuse together when these collisions are powerful enough. The main fusion process turns four hydrogen nuclei (protons) into one helium nucleus through several steps. Here’s how it works:
- Two protons fuse to form deuterium (a hydrogen isotope), releasing a positron and a neutrino
- The deuterium fuses with another proton to create helium-3
- Two helium-3 nuclei combine to form helium-4 plus two protons
The chance of these fusion reactions happening is surprisingly low because the conversion depends on the weak nuclear force, which works much slower than the strong nuclear force. A typical proton in the sun’s core has a half-life of about 10 billion years. This explains why our star can keep producing energy for billions of years.
Energy Production: 600 Million Tons per Second
The sun’s core turns 600-620 million metric tons of hydrogen into helium every second through nuclear fusion. The resulting helium atoms weigh slightly less than the original hydrogen atoms. This missing mass becomes pure energy following Einstein’s famous equation E=mc².
About 4.26 million metric tons of matter transform into pure energy every second. This energy release is 10 million times greater than what happens when hydrogen combines with oxygen to make water. The sun’s total power output reaches an incredible 3.86 × 10^26 joules per second.
This massive energy output creates an outward pressure that balances against the sun’s inward gravitational pull. This balance keeps our star from collapsing or exploding. The core regulates itself remarkably well – if fusion slows down, the core contracts and heats up, which speeds fusion up again, and vice versa.
The photons created in the core begin an amazing trip outward after they’re generated. The core’s extreme density makes these photons bounce around continuously. They take about 170,000 years to travel from the core to the top of the convection zone before finally reaching us as sunlight.
Radiative Zone: The 350,000-Year Journey
The sun’s nuclear fusion powerhouse has a neighboring layer that moves energy from its core to outer regions. Scientists call it the radiative zone because of how it transfers energy. This layer begins at approximately 25% of the distance to the solar surface and stretches to about 70% of that distance. This region serves as a vital energy highway and makes up the sun’s second interior layer.
Chemical Composition at 7 Million Degrees
The radiative zone’s temperature reaches an incredible 7 million degrees Celsius where it meets the core. The temperature drops to about 2 million degrees Celsius at its outer edge. This temperature difference determines how energy flows through the region.
Material density changes drastically throughout the radiative zone. The inner boundary’s density matches that of gold at about 20 g/cm³. This number drops to 0.2 g/cm³ at the upper boundary, which is nowhere near water’s density.
Extreme heat in this zone affects everything in it. The temperature, though lower than the core’s, prevents atoms from staying whole. Notwithstanding that, some atoms keep enough structure to interact with passing radiation. These atoms absorb energy, hold it briefly, and release it as new radiation.
The radiative zone stays remarkably stable, unlike the churning plasma in the core. High density gradient causes this stability. Material moving upward becomes less dense from expansion, but not as much as its surroundings. This creates a downward force, keeping the zone calmer than other solar regions.
How Photons Travel Through This Dense Region
Light’s experience through the radiative zone ranks among our solar system’s most fascinating stories. Photons zip through space at 300,000 kilometers per second, but their path here becomes incredibly complex.
Photons from nuclear fusion face a huge challenge in the radiative zone: tightly packed particles. These particles crowd so closely that photons travel only millimeters before hitting another particle. Each collision triggers three events:
- The photon is absorbed by the particle
- The particle briefly stores the energy
- The energy is re-emitted as a new photon in a random direction
Photons bounce around randomly in this process. They might move toward the surface, back to the core, or sideways. Direct paths between the zone’s ends don’t exist.
This random walk creates mind-boggling results. Each photon moves at light speed between collisions, but the total journey takes much longer. Scientists believe energy needs between 171,000 and 350,000 years to cross the radiative zone. Some research suggests up to a million years.
The average photon moves just 1 centimeter every 10 minutes in the radiative zone. This seemingly slow process remains the quickest way to transport energy through this solar region.
The radiative zone works like a massive energy storage system, holding vast amounts of solar power in transit. This explains the sun’s makeup beyond its chemical elements. Each layer uses different energy transport methods that suit their conditions.
Photons reaching the radiative zone’s outer edge meet the tachocline. This transition layer between the radiative and convection zones marks another radical alteration in the sun’s composition and energy transport systems.
The Tachocline: Boundary of Magnetic Activity
The tachocline, a remarkable boundary layer, sits between the calm radiative zone and the turbulent convection zone of the Sun. Scientists used helioseismology to find this thin transitional region that plays a vital role in the Sun’s magnetic behavior and shapes what we see on the solar surface. The sort of thing I love about the tachocline is that it contains the strongest rotational shear found anywhere in the Sun.
Unique Elemental Behavior in the Transition Layer
The Sun’s internal rotation changes dramatically at the tachocline. This narrow layer marks where the differential rotation pattern of the outer convection zone changes to the solid-body rotation of the interior radiative zone. The layer shows a distinctly prolate (elongated) shape, positioned about 0.693 solar radii from the center at the equator and 0.717 solar radii at higher latitudes.
The tachocline’s chemical composition behavior makes it unique. Helioseismic studies show major changes in how elements distribute across this boundary. Helium from the convection zone sinks under gravity into the tachocline, and complex circulation patterns mix this material back into the convection zone. This mixing reduces the mean molecular weight within the tachocline region and increases the sound speed. This mixing helps explain why the actual Sun’s sound speed measurements exceed standard solar model predictions, with observed differences (δc²/c² ≈ 0.004) at this boundary.
The tachocline experiences powerful shear forces beyond its compositional features. Both radial and latitudinal shears in this region show significant changes throughout the solar cycle, with notable differences between cycles 23 and 24. These strong shearing motions stretch magnetic field lines and generate massive toroidal magnetic fields reaching approximately 100 kilogauss. These intense magnetic fields become buoyant enough to rise through the convection zone and emerge as sunspots at specific latitudes on the solar surface.
NASA’s Helioseismology Measurements
NASA’s helioseismic observations have transformed our understanding of this vital solar layer. Scientists measured solar oscillations and learned the tachocline’s thickness is less than 5% of the solar radius. These measurements confirmed the tachocline’s position, with about one-third in the slightly subadiabatic overshoot layer and the rest in the strongly subadiabatic radiative zone.
NASA’s findings about temporal variations in the tachocline stand out. Data from the Solar and Heliospheric Observatory (SOHO) and Solar Dynamics Observatory (SDO) showed substantial changes in rotation rates near the tachocline. These variations measure about 6 nanohertz (nHz) and occur out of phase above and below the tachocline—a big fluctuation compared to the 30 nHz drop in rotation rate across the entire tachocline at the equator. Higher latitudes show even greater amplitude variations that follow a period close to but distinct from one year.
Some helioseismic analyses point to large-scale oscillations across the tachocline with a period of about 1.3 years. Scientists estimate the tachocline contains magnetic fields with radial components around 500 gauss, based on these Alfvénic torsional oscillations.
The tachocline serves as the heart of the Sun’s magnetic behavior. Many solar physicists see this layer as the main location of the solar dynamo—the mechanism behind the Sun’s 11-year activity cycle and 22-year magnetic cycle. NASA’s Parker Solar Probe and Solar Orbiter missions continue to explore how the tachocline’s magnetic activity extends through the solar atmosphere and beyond. These missions help us learn about the Sun’s composition and how these materials behave under extreme conditions.
Convective Zone: Churning Solar Materials
The sun’s most dynamic interior region, the convective zone, sits just beyond the tachocline. This turbulent layer covers the outer 30% of the solar interior. It stretches from about 200,000 kilometers below the visible surface all the way to the photosphere. The way energy moves in this region changes from radiation to convection, which creates fascinating patterns we can see on the sun’s surface.
Element Distribution in Solar Plasma
The convective zone’s plasma contains mostly hydrogen (70% by mass) and helium (27.7% by mass), with tiny amounts of carbon, nitrogen, and oxygen mixed in. The temperature and density change substantially as you move through this layer. The base near the tachocline reaches temperatures of about 2 million degrees Celsius. The surface cools down to about 5,700 degrees Celsius.
These temperature differences create ideal conditions to understand what makes up the sun’s outer regions. The material becomes clearer as you get closer to the surface. The density drops to just 0.0000002 g/cm³ at the photosphere – roughly 1/10,000th as dense as Earth’s air at sea level. This huge density drop lets convection work quickly and effectively.
The cooler temperatures here let heavier ions like carbon, nitrogen, oxygen, calcium, and iron keep some of their electrons. These partially ionized elements make the material harder to see through, which traps heat and drives the convective instability.
Rising and Falling Material Patterns
The convective zone works just like a pot of boiling water. Hot plasma rises from the bottom and expands as it moves up into areas with less pressure. It then cools at the surface where energy escapes as light. The cooled, denser material sinks back down in a never-ending cycle.
These convective motions show up as distinct patterns:
- Granules: Small cells about 700-1,000 kilometers across (roughly Texas-sized) that last only 5-10 minutes
- Supergranules: Massive cells about 35,000 kilometers wide (twice Earth’s size) that stick around for about 24 hours
Bright areas in these structures show hot plasma rising at 2-3 kilometers per second, while darker spots indicate cooler material sinking back into the sun. The cells get smaller with height throughout the convective zone, creating complex layers of turbulent patterns.
NASA’s Solar Dynamics Observatory Findings
NASA’s Solar Dynamics Observatory (SDO) has transformed our understanding of solar convection. The spacecraft takes pictures ten times clearer than high-definition TV, letting scientists examine convective patterns in incredible detail.
SDO shows that convective cells organize themselves in remarkable ways. Larger cells break into smaller ones near the surface. Downflow lanes at low solar latitudes tend to point north-south and move east compared to surrounding plasma. Solar cyclones form where these lanes meet at higher latitudes – spinning counterclockwise up north and clockwise down south.
Scientists use SDO’s Helioseismic and Magnetic Imager (HMI) to look beneath the surface and measure the convection zone’s properties. These measurements confirm that solar rotation substantially affects convective motions through the Coriolis force. This creates differential rotation patterns that change with both latitude and depth.
This complex dance between turbulent convection and differential rotation creates electric currents and magnetic fields through the solar dynamo mechanism. The sun’s basic ingredients shape everything we see, from its granulated surface to its dynamic magnetic behavior.
The Photosphere: Visible Surface Composition
Image Source: NASA
Light from the sun comes from an incredibly thin layer called the photosphere – the visible “surface” that lights up Earth and lets us see our star. Most people think this surface is solid, but it actually consists of plasma approximately 100-500 kilometers thick – only 0.07% of the sun’s radius. This photosphere gives us most of the solar radiation that reaches Earth and helps us understand the sun’s composition.
Spectroscopic Analysis of the Sun’s ‘Surface’
Scientists use spectroscopy to study the photosphere by looking at dark absorption lines that break up white light’s continuous spectrum. These spectral patterns show almost every element exists there. Hydrogen makes up 74.9% and helium accounts for 23.8% of the total mass. Stellar astronomers call the leftover elements “metals,” which make up less than 2% of the photospheric mass.
Scientists need complex modeling techniques to get this composition data. They create numerical model atmospheres and calculate theoretical spectra to compare with what they observe. New three-dimensional, time-dependent hydrodynamical models have replaced older one-dimensional approaches. These better models show lower amounts of carbon, nitrogen, oxygen, and neon than we thought a decade ago.
Abundance of Elements in Solar Granules
Specialized instruments show the photosphere has a distinctive granular pattern. Bright cells with darker boundaries create these granulation patterns. Each granule stretches about 1,000 kilometers – about as wide as Texas – and lasts just 5-10 minutes. Hotter plasma rises at about 7 km/s in brighter areas while cooler material sinks back into the sun through darker boundaries.
Different elements spread unevenly in these granular structures. The most common trace elements are oxygen, carbon, nitrogen, iron and magnesium. The photosphere stays around 5,500°C (9,900°F) on average, though temperatures vary in different areas. This makes the photosphere nowhere near as hot as the sun’s core or corona, but it still keeps matter in a highly ionized plasma state.
Sunspot Chemistry and Structure
Sunspots show up as darker, cooler regions in the photosphere with temperatures around 4,200K – about 1,800K cooler than nearby areas. Each sunspot usually has a dark center called the umbra with a lighter outer region called the penumbra. Strong magnetic fields block hotter gases from flowing, which creates these cooler, darker areas.
George Hale found sunspots had strong magnetic fields in 1908. He saw the Zeeman effect in their spectral lines – a splitting pattern that happens when atoms interact with magnetic fields. These fields point either straight out (positive polarity) or straight in (negative polarity), and sunspot groups often have pairs with opposite polarities.
Sunspot penumbrae have interesting features with horizontal magnetic fields that create overlapping white and gray patterns. Bright chromospheric areas called faculae or filigree often appear near sunspots with magnetic field strengths between 0.10 to 0.20 tesla.
Better solar telescopes and faster computers have boosted our knowledge of sunspot structures. New developments suggest we will learn even more about the photosphere.
Solar Atmosphere Layers: Changing Compositions
Image Source: PMF IAS
The sun’s atmosphere stretches above the photosphere. This remarkable realm showcases dramatic changes in temperature and composition. The sun’s atmospheric layers grow hotter as they extend from its surface, unlike Earth’s atmosphere that cools with altitude. These distinct zones exhibit unique chemical behaviors.
Chromosphere’s Unique Chemical Signature
The chromosphere (“color sphere”) sits right above the photosphere. This irregular layer extends about 2,000 kilometers upward. Temperatures in this region rise sharply from 6,000°C to approximately 20,000°C. Hydrogen atoms emit H-alpha light that creates the chromosphere’s distinctive reddish glow during solar eclipses.
Specialized filters reveal the chromosphere’s fascinating features. Scientists can observe the chromospheric network of magnetic field elements, bright plage around sunspots, and dark filaments across the solar disk. This layer might play a vital role as it conducts heat from the sun’s interior to its outermost atmosphere.
Corona’s Mysteriously Hot Plasma at 1 Million Degrees
The corona extends millions of kilometers into space and presents one of solar physics’ greatest mysteries. The corona reaches temperatures between 1 to 3 million Kelvin—approximately 150 to 450 times hotter than the photosphere, despite being farther from the solar core. This temperature inversion challenges simple thermodynamic principles since heat shouldn’t flow from cooler to hotter regions.
Scientists propose several mechanisms to explain this phenomenon. Millions of “nanoflares”—tiny explosions with one-billionth the energy of regular flares—might provide sporadic bursts reaching up to 18 million degrees Fahrenheit. Recent observations from the European-U.S. Solar Orbiter suggest that solar “campfires” (miniature solar flares) could contribute to coronal heating.
Solar Wind Particle Composition
Charged particles stream outward from the corona at several hundred kilometers per second, forming the solar wind. This plasma contains:
- 95% protons (H+)
- 4% alpha particles (He++)
- 1% minor ions including carbon, nitrogen, oxygen, and heavier elements
The solar wind’s composition changes based on its source region. The “slow” solar wind (300-500 km/s) matches coronal composition closely. The “fast” solar wind (750 km/s) reflects the photosphere’s makeup more accurately. Scientists have identified trace amounts of rarer elements through precise measurements. These include phosphorus, titanium, chromium, and nickel isotopes (58Ni, 60Ni, 62Ni).
What Type of Star is the Sun? G-Type Classification
Image Source: faculty.wcas.northwestern.edu
Astronomers group the stars in our universe by their temperature, luminosity, and composition. Our sun belongs to a category that tells us about its composition and its place in stellar progress.
Metallicity and Spectral Characteristics
Astronomical metallicity measures the abundance of elements heavier than hydrogen and helium. These “metals” make up less than 2% of the sun’s mass, but they affect its behavior by a lot. A researcher pointed out that “Even a very small fraction of metals is sufficient to alter the behavior of a star completely”. The sun’s metallicity is a vital reference point to calibrate measurements of other stars across the cosmos.
Our sun belongs to the G-type spectral class, labeled as G2V. G2 shows it’s the second hottest subcategory of yellow-white stars with surface temperatures between 5,300 and 6,000 K. The V identifies its luminosity class as a main-sequence star. G-type stars show strong spectral lines H and K of Ca II, and they display neutral metals and weaker hydrogen lines than F-class stars.
Comparison to Other Main Sequence Stars
Main sequence stars make up about 90% of all stars in the universe. G-type main-sequence stars like our sun represent about 7.5% of main-sequence stars near our solar system. These stars use nuclear fusion to convert hydrogen into helium in their cores. They stay stable for billions of years through a balance called hydrostatic equilibrium.
The sun’s mass ranges between 0.9 and 1.1 solar masses, and it shines brighter than about 90% of stars in the Milky Way. Red dwarfs make up about 75% of our galaxy’s stars, but G-type stars live longer – between 7.9 and 13 billion years. Scientists expect our sun to stay on the main sequence for about 10 billion years.
Position on the Hertzsprung-Russell Diagram
The Hertzsprung-Russell diagram serves as a fundamental tool in stellar astronomy. Our sun sits “nearly in the middle” of the main sequence on this diagram. It has a luminosity of 1 (absolute magnitude 4.8) with a B-V color index of 0.66. This central spot in the diagonal band, which runs from hot, bright stars to cool, dim ones, shows that the sun is a typical middle-aged star that actively fuses hydrogen.
NASA’s Tools for Studying Solar Composition
Image Source: Science News
NASA sends advanced spacecraft closer to the sun than ever before to discover its compositional mysteries. These specialized observatories gather vital data about the sun’s makeup. They use different methods that range from direct sampling to remote spectroscopy.
Parker Solar Probe’s Close Encounters
NASA’s Parker Solar Probe achieved a historic milestone on December 14, 2021. It became the first spacecraft to “touch” the sun by flying through its corona. This remarkable piece of engineering comes within 3.9 million miles of the solar surface. A 4.5-inch carbon-composite shield protects it from temperatures reaching 2,500°F. The probe’s instruments study solar wind particles and show how solar material flows into space.
Recent findings from 2023 show that Parker detected intricate solar wind patterns near its source. It found magnetic funnels about 18,000 miles wide where particle reconnection creates extraordinary speeds. These particles move 10 to 100 times faster than typical solar wind. These measurements give scientists a unique look at how elements behave on the sun’s surface.
Solar Orbiter’s Spectroscopic Instruments
The Solar Orbiter works alongside Parker with its advanced spectroscopic tools to study the sun’s composition from afar. Its Spectral Imaging of Coronal Environment (SPICE) instrument watches two extreme ultraviolet wavelength bands (70.4-79.0 nm and 97.3-104.9 nm). This helps map elements across temperature ranges from the cooler chromosphere (20,000K) to the intense corona (10 million K).
SPICE captures complete spectral data in just one second. Scientists can track element movement between solar layers with this capability. The instrument’s main strength comes from its ability to capture emission lines from different temperature zones at once. This creates exceptional compositional snapshots in single exposures.
Solar Dynamics Observatory’s Elemental Mapping
The Solar Dynamics Observatory (SDO) has transformed our knowledge of solar composition through non-stop, high-resolution monitoring. Its Atmospheric Imaging Assembly (AIA) takes pictures in seven extreme ultraviolet channels that mainly show different states of ionized iron. Scientists use these observations to create temperature maps ranging from below 1 million Kelvin to above 20 million Kelvin.
SDO’s Extreme Ultraviolet Variability Experiment (EVE) measures the sun’s spectral output with amazing detail. It achieves 10-second time resolution and better than 0.1 nm spectral resolution. Scientists can now track changes in solar composition during eruptions and throughout activity cycles.
Conclusion, what is the answer to what is the sun made of
The sun’s composition reveals an intricate stellar structure with nuclear fusion powering its core. Nuclear reactions transform hydrogen into helium and release enormous energy that flows through several distinct layers. Each layer plays a vital role in energy transport and magnetic field generation.
Our star’s internal structure extends from a core heated to 15 million degrees to the radiative zone. Photons take hundreds of thousands of years to move outward through this zone. The tachocline layer creates a significant boundary between internal regions and generates powerful magnetic fields that influence solar activity. Energy moves through the outer layers by convection processes that we can observe at the photosphere.
Scientists now use advanced solar observatories to study our star’s makeup and behavior. The Parker Solar Probe, Solar Orbiter, and Solar Dynamics Observatory from NASA collect essential data about solar wind particles. These missions also analyze spectroscopic signatures and track how elements spread throughout the sun’s atmosphere.
Scientists can better predict solar activity and understand stellar development because they know our star’s composition. The sun represents a typical G-type star while serving as an exceptional laboratory. It helps researchers study fundamental astrophysical processes that influence our cosmic neighborhood.
FAQs
Q1. What is the primary composition of the Sun? The Sun is composed mainly of hydrogen (about 71% by mass) and helium (about 27% by mass). The remaining 2% consists of heavier elements like oxygen, carbon, neon, and iron.
Q2. How does the Sun generate its energy? The Sun produces energy through nuclear fusion in its core. Hydrogen atoms fuse to form helium at temperatures of about 15 million degrees Celsius, releasing enormous amounts of energy in the process.
Q3. What would happen if you brought a piece of the Sun to Earth? If you could hypothetically bring a piece of the Sun to Earth, it would rapidly expand and explode violently due to the sudden release of pressure. The Sun’s material is only contained by its own massive gravity.
Q4. How hot is the surface of the Sun? The surface of the Sun, known as the photosphere, has a temperature of approximately 5,500 degrees Celsius (9,932 degrees Fahrenheit).
Q5. What tools does NASA use to study the Sun’s composition? NASA employs various advanced spacecraft to study the Sun, including the Parker Solar Probe, which flies through the Sun’s corona, the Solar Orbiter with its spectroscopic instruments, and the Solar Dynamics Observatory, which provides high-resolution monitoring of the Sun’s surface and atmosphere.